GM GENUINE PARTS locking fuel tank cap GT139L (25060147) — OEM threaded replacement, rubber gasket & optional check valve

This locking fuel cap is an original-equipment replacement made to GM specifications for vehicles that require a threaded locking cap. It combines a rubber gasket for a liquid-tight seal with an optional pressure check valve to equalize tank air pressure. Built to the same dimensional and material standards as the factory part, the GT139L restores proper sealing, prevents contaminants from entering the tank, and limits unauthorized fuel access.

How does the GT139L maintain a secure seal?

The cap uses a molded rubber gasket and precision threads to create a reliable, liquid-tight barrier between the fuel tank and the environment. Proper sealing helps prevent fuel loss, keeps moisture and dirt out of the filler neck, and preserves onboard vapor control systems.

• Rubber gasket forms a tight contact with the filler neck sealing surface.
• Threaded design matches factory engagement depth and torque.
• Durable materials resist fuel and weather exposure over time.

Does this cap include a pressure or check valve?

Some GT139L caps include an internal check valve that responds to differential pressure inside the tank. The valve allows air movement to equalize pressure as needed while retaining a sealed barrier against liquid fuel and contaminants.

• Check-valve operation admits or vents air depending on tank pressure.
• Helps maintain proper evaporative system performance when applicable.
• Valve design is integrated without compromising the locking mechanism.

What security benefits does the locking feature provide?

The integrated lock deters fuel theft and unauthorized access at the filler. It’s a simple mechanical way to protect fuel and peace of mind, particularly for vehicles parked in public or unattended locations.

• Keyed lock secures the cap to the filler neck to prevent removal.
• Same key options and replacement keys available through GM dealers.
• Lock housing and shank built to resist tampering and corrosion.

Will this cap fit my GM vehicle and how do I install it?

GT139L is a vehicle-specific part designed to match the original equipment cap on qualifying GM models. Installation is straightforward: thread the cap onto the filler neck until the gasket seats, then lock if applicable. Always verify part number compatibility with your VIN or vehicle year/model before purchase.

• Direct-fit replacement for the corresponding GM part number 25060147.
• No special tools required for standard installation—hand-tighten per factory guidance.
• Confirm fit by cross-referencing GM part listings or dealer lookup.

Who is this for: The GM Genuine Parts GT139L locking fuel cap is intended for owners and technicians who need a factory-equivalent replacement for a GM vehicle that originally used a threaded locking fuel cap. It suits drivers who want to restore proper sealing and evaporative function, reduce the risk of fuel theft, or replace a worn or damaged cap with a GM-specified component. Ideal for maintenance shops, fleet managers, and vehicle owners seeking OEM fit, reliable sealing performance, and a built-in locking option.